Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class KarenGame implements Runnable {
	StringBuffer sb = new StringBuffer("");
	int n, m;
	int cnt = 0;
	private void solve() throws IOException {
		// long time = System.currentTimeMillis();
		n = nextInt();
		m = nextInt();
		int[][] target = new int[n][m];
		for (int i = 0; i < n; i++)
			for (int j = 0; j < m; j++) target[i][j] = nextInt();

		if (n < m) {
			doRow(target);
			doColumn(target);
		} else {
			doColumn(target);
			doRow(target);
		}

		if (!isValid(target)) {
			System.out.println(-1);
		} else {
			System.out.println(cnt);
			System.out.println(sb.toString());
		}

		// writer.println("Running time: " + (System.currentTimeMillis() -
		// time));
	}

	boolean isValid(int[][] a) {
		for (int[] arr : a) for (int n: arr) if (n > 0) return false;
		return true;
	}

	void doRow(int[][] a) {
		for (int i = 0; i< n; i++) {
			int min = Integer.MAX_VALUE;
			for (int j = 0; j < m; j++) min = Math.min(min, a[i][j]);
			for (int j = 0; j < m; j++) a[i][j] -= min;
			for (int j = 0; j < min; j++) sb.append("row " + (i+1)).append("\n");
			cnt += min;
		}
	}

	void doColumn(int[][] a) {
		for (int i = 0; i< m; i++) {
			int min = Integer.MAX_VALUE;
			for (int j = 0; j < n; j++) min = Math.min(min, a[j][i]);
			for (int j = 0; j < n; j++) a[j][i] -= min;
			for (int j = 0; j < min; j++) sb.append("col " + (i+1)).append("\n");
			cnt += min;
		}
	}


	public static void main(String[] args) {
		new KarenGame().run();
	}

	BufferedReader reader;
	StringTokenizer tokenizer;
	PrintWriter writer;

	public void run() {
		try {
			reader = new BufferedReader(new InputStreamReader(System.in));
			tokenizer = null;
			writer = new PrintWriter(System.out);
			solve();
			reader.close();
			writer.close();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}

	long nextLong() throws IOException {
		return Long.parseLong(nextToken());
	}

	double nextDouble() throws IOException {
		return Double.parseDouble(nextToken());
	}

	String nextToken() throws IOException {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			tokenizer = new StringTokenizer(reader.readLine());
		}
		return tokenizer.nextToken();
	}
}